Speaker Review Anechoic Measurements- Grossly Inadequate and Why

[MaxwellsEq]

without bouundary reinforcement, more so than the sound radiated directly from the drivers.

Have you been in an anechoic chamber? I have, and it's a strangely uncomfortable experience.

Imagine in our anechoic chamber is a speaker built with wobbly walls playing pink noise quietly, but inside the speaker is a device banging on the sidewall much louder than the pink noise. Measuring the speaker at, say 3m, you will record the white noise from the drivers and the contribution from the side panel being hammered. This would happen even an anechoic chamber with no reflections, or on 50' tall pole in a field.

The reality is that external cabinet contribution are not very significant, unlike internal standing waves and room nodes

 

[avanti1960]

Have you been in an anechoic chamber? I have, and it's a strangely uncomfortable experience.

Imagine in our anechoic chamber is a speaker built with wobbly walls playing pink noise quietly, but inside the speaker is a device banging on the sidewall much louder than the pink noise. Measuring the speaker at, say 3m, you will record the white noise from the drivers and the contribution from the side panel being hammered. This would happen even an anechoic chamber with no reflections, or on 50' tall pole in a field.

The reality is that external cabinet contribution are not very significant, unlike internal standing waves and room nodes

I have and yeah, it is so quiet it is strange at first. I get what you are saying but at the same time certain frequencies of the cabinet resonance are more directional than others. I can't help but think that resonances from the rear, top and side panels will be louder on their axis than when measured from the axis of the drivers. This has to be reinforced by a typical in room position.

I realize the conclusions are not scientific, but when I look at a speaker with a bass boosted response plot (that is often highly criticized) but yet it measures well in room because it has no cabinet resonance in the bass / midbass frequencies, how can a response plot be of value to predict how it will sound?
When I look at a relatively even response plot that would be applauded, yet the cabinet resonance is lossy by design and the in-room response is horribly unacceptable, what value is there in the original measurement plot? In these instances you cannot predict in-room response (where it matters) you also cannot predict how one speaker will sound relative to another with a different response plot.

 

[MAB]

I realize the conclusions are not scientific, but when I look at a speaker with a bass boosted response plot (that is often highly criticized) but yet it measures well in room because it has no cabinet resonance in the bass / midbass frequencies, how can a response plot be of value to predict how it will sound?

Because the non-scientific conclusions started with an incorrect assumption: that the reason the speakers sound good is due to the lack of cabinet resonance. Cabinet resonances are typically orders of magnitude lower than the speaker's output, and contribute only a very tiny amount to the actual sound. All of those great sounding speakers sound great because of other aspects of the design that are way more important than cabinet resonances. You are incorrectly elevating the importance of cabinet resonances.

 

[MaxwellsEq]

I can't help but think that resonances from the rear, top and side panels will be louder on their axis than when measured from the axis of the drivers. This has to be reinforced by a typical in room position.

but when I look at a speaker with a bass boosted response plot

When I look at a relatively even response plot that would be applauded

The problem is this: you look at some plots generated in certain way. Then you look at some other plots generated in a different way. Then you generalize based on comparing these plots. Then you propose a mechanism for your extrapolated generalization. The mechanism you propose is that cabinet emanations with floor, ceiling and wall reflections must contribute a lot to how a speaker sounds - and that these reflected emanations would not be captured in an anechoic chamber where the microphone is only ever pointed at the drivers and front plate.

Cabinet emanations are quite low level. Reflections of cabinet emanations are lower level still. Many plots these days rotate the speaker, simply to measure off-axis behaviour. Standing waves are a function of the room.

 

[kemmler3D]

I can't help but think that resonances from the rear, top and side panels will be louder on their axis... how can a response plot be of value to predict how it will sound?

Well, the shortcomings of a single on-axis measurement are why we (ideally) do spinoramas now, i.e. measurements from all angles.

 

[krabapple]

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